De la Vega M G, Cejudo F J, Paneque A
Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-Consejo Superior de Investigaciones Científicas, Spain.
Appl Biochem Biotechnol. 1991 Sep;30(3):273-84. doi: 10.1007/BF02922031.
Environmental conditions affect the production of extracellular polysaccharide by Azotobacter chroococcum ATCC 4412. Production of exocellular polymer from a variety of carbon sources depended on the air flow rate. A high sucrose concentration in medium (8%) markedly favored expopolysaccharide production, which reached 14 g/L in about 72 h. In cell suspensions incubated in the presence of 8% sucrose in a nitrogen-free medium, biopolymer final concentration of 9 g/L corresponds to 68 g/g biomass. Maximum efficiency of sucrose conversion into exopolysaccharide peaked at 70% for initial disaccharide concentration of 6%. High performance liquid chromatography and gas liquid chromatography of acid hydrolysates of the exopolymer revealed the presence of mannuronosyl, guluronosyl, and acetyl residues, but not neutral sugars. The infrared spectrum corroborated the presence of carboxylate anions and O-acetyl groups in the exopolymer. Though the presence of more than one kind of polysaccharide cannot be ruled out, these data suggest that, under the experimental conditions used in this work, only a type of alginate-like exopolysaccharide is produced by A. chroococcum ATCC 4412.
环境条件影响褐球固氮菌ATCC 4412胞外多糖的产生。从多种碳源产生胞外聚合物取决于空气流速。培养基中高蔗糖浓度（8%）显著有利于胞外多糖的产生，在约72小时内可达14 g/L。在无氮培养基中8%蔗糖存在下孵育的细胞悬液中，生物聚合物最终浓度为9 g/L相当于68 g/g生物量。对于初始二糖浓度为6%，蔗糖转化为胞外多糖的最大效率在70%时达到峰值。胞外聚合物酸水解产物的高效液相色谱和气相色谱显示存在甘露糖醛酸基、古洛糖醛酸基和乙酰基残基，但不存在中性糖。红外光谱证实胞外聚合物中存在羧酸根阴离子和O - 乙酰基。尽管不能排除存在不止一种多糖，但这些数据表明，在本研究使用的实验条件下，褐球固氮菌ATCC 4412仅产生一种藻酸盐样胞外多糖。
